The president says it's the longest streak in history. And back overseas, a day that began with a 72-hour cease-fire saw it shattered before it began. One of the soldiers apparently captured by hamas. Terry Moran is in gaza for us tonight. Reporter: This morning, when the cease-fire took hold, there was quiet in gaza. You could hear the birds chirp. And so the people of this battered land emerged from hiding to return home to what was left of their homes. Then, it was on again. Each side accusing the other of violating the cease-fire. It happened at one of those hamas tunnels Israel has vowed to destroy. Israeli officials saying an army unit had been ambushed as they were clearing a tunnel after the cease-fire commenced. Two soldiers killed, and one, apparently, captured. The nightmare scenario for Israel. The missing soldier, 23-year-old lieutenant hadar Goldin, engaged to be married, his twin brother in the army too. And his father confident. We are certain the army will not stop. And will bring hadar back home, safe and sound. Reporter: President Obama today demanding lieutenant Goldin's return. That soldier has to be unconditionally released as soon as possible. Reporter: We saw firsthand this week how wary Israeli forces are of these tunnels. Guns drawn, pointed down the shaft, ready for anything. But you won't go in? No. Reporter: Assumption, booby trapped. Assumption, booby trapped and maybe terrorists inside. Reporter: But today, at a U.N. Shelter here in gaza, Palestinians told us the capture of an Israeli is a triumph. I think this is a right for Palestinians to defend themselves. Reporter: Now, with Israeli forces pressing hard, looking for their comrade, the war is intensifying with no end in sight. Terry Moran, ABC news, gaza.

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